Furnace.



'PATENTED APR. 28; 1908 0. W. sMiTH. FURNACE. APPLICATION FILED 1130.29.1905.

2 SHEETSSHBET 1 UNITED STATES CLARENCE W. SMITH,OF CAMBRIDGE,MASSACHUSETTS.

FURNACE.

Application filed December 28, 1905. Serial No. 293,577.

To all whom it may concern:

Be it known that I, CLARENCE W. SMITH, of Cambridge, in the county ofMiddlesex and State of Massachusetts, have invented certain new anduseful Improvements in Furnaces, of which the following is aspecificatron.

My invention relates to-furnacesand more particularly to thoseapplicable to steam oilers. Its rincipal object is to provide a furnace.Whic 'will attain a high degree of efiiciency .in the consum tion ofvarying grades of fuel. To accomplish this, the exact amount of airrequired for perfect combustion should be presented to the burning fuel,since too little will result in a deadening of the fire, and waste frompartly burned gases, and an excess means the lowering of the the boxtemperature, waste of fuel in heating needless air and the, overloadingof the stack.

The air must also be uniforrnl diffused through the ash-pit, otherwiseloweholes will be made in the burning fuel, causing wasteful excess ofair and the formation of clinker and sla from the intense local action.These desirab e results mentioned, which have been heretoforeimperfectly attained in' plants using forced or induced draft, aresecured by my invention.

In the accompanying drawings, in which similar characters designate likeparts i througlhout'the several views-Figure 1' is a contra verticallongitudinal section through a boiler and its furnace, embodying oneform of my invention. Fig. 2 is a transverse vertical section therethrouh, and Fig. 3 is a sectional detail through t e outlet openings in thetop of the bridge-wall.

The furnace 10, as here shown, is formed in the masonry inclosing aboiler 11. It comprises a grate'12 supported between the front of thestructure and a bridge-wall 13, and has beneath it an ash-pit 14.Extending throu h the bridge-wall in a gcnerally'horizonta direction,and opening into the ash-pit beneath the grate is a passage or conduit15. Above this passage a second passage 16, or a plurality thereof, asis shown in the present instance, opens from the ash-pit extendingthrough the bridge wall, first in a horizontal direction and thenvertically, diverging upwardly to a considerable number of corn tractodopenings 17. These may be formed of fire-resisting tile 18 in a recessat the top of the bridge wall so that their" tops are flush with the topof the bridge-wallf The Specification of Letters Patent.

Patented April 28, 1808.

o epings 17 are preferably tapered, having t on minimum diameter at theupper ends. Between the openings of the passages 15 and 16 is situated adeflector 19, which 1s inclined downwardly from the grate, across theend of the former passage. The deflector may be curved, as 1 lustrated,its convex side being outward.

or condu it 20 lying across the furnace and being continued outside thecasing by. a. pipe 21, leading to the movable air-supplying ,arm 28 anda bevel pinion 29 which meshes with a bevel gear 30 fast upon a shaft31. This shaft has secured at its oppositccx tremity a crank-disk 32,the pin of which is connected with some convenient form ofressure-regulating device 34, joined to the su ply under pressure bypipe 36.

n using my im roved furnace, air is drawn by the fan t trough the pipe23 and forced into the passage 15in the'bridge-wall against the curveddeflector, by which it is directed against the lloor of the ash-pit,over which it flows and rises in equal di'l'l'usion through all arts ofthe grate. The dcflector extending the full width of the fireboxeffectually prevents the escape upward of air at the sides of thepussuge 15, with consequent excess of draft and blow-holes in .the fuelat that end of the grate. A part of the air )asses into the passugo l6and delivered by the contracted openings into gases trm'eling over thelu'idgwwnll. The taper of these-o innings prevents the :u-r-umulation ofash, While their reduced outlets give the ejected. air a high velocityand penetrating power, intimately mingling it with the gases oven at theends of the will when the spaces between it and the shell of the boiledare 1 widest. The secondary air-simply, antrol l -ducou abo\ e thelet-cl oi the top of fucl Atthe rear of the bridge-Wall is a chamber.

means which is shown as a blower 22, having.

trolling the motor speed. The spindle 27 of the rheostat has fixed to itthe usual contact- Joiler by pipe 35, and to a source of water whichisressential for complete combustion. of thcvalnable gases distilled oiland the pre vention of smoke, is" thus provided. ".lhe' air after beingwarmed in the pipe 23 and con duits 20 and is spread under the grate bythe deflector l9 and heated there, and then the air which returns intothe bridgeavall on its-way to the contracted openings 17 is highlyheated before issuing through said openings. If the pressure in theboiler varies from the desired amount, the reg ulator automaticallyshifts the contact-arm of the rheostat, thus varying the currentdelivered to the motor to increase or decrease its speed and thatohthefan, thus increasing or decreasing the volume of the airideliveredto the furnace as ma "be necessary. The

regulat onpfa r supp 'y to the furnace ands consequent steam pressureiii the boiler cfsupply ofhir from that heated by 'fected by thisarrangement is very erfect,

but'little resistance being offered by t is contact-arm. to'itsmoveinent by the, pressure regulator. And as the contact'blocks andconnected resistance *coilsare numerous, a high degree of sensitivenessis attained. This automatic control of the air-supply and thediffusion'of air through the bed of fuel and through the escapin Indrawing the the boiler, it 15 not only delivered to the fire at atornperaturc raised to an effective degree, but the boiler-rodm is alsorendered more com-- it practih lly smolieless;

fortable by the withdrawal ofthe hot air.

Though Lhave described my invention as ap lied to a steam boiler satinmasonry, it will be seen that it is by no means limited to such anapplication, but that it may be used in connection with-furnaces of manytypes.

I claim: I

1. A furnace comprising a grate, a bridgewall provided with a assageterminating'in a series of contracts openings in its upper portion saidpassage openin beneath the grate and a second passage a so openingbeneath the grate, means for forcing air to the space beneath the grate,means for distiibut 'ing the air beneath the grate, and automatic meansfor governing the air-forcing means responsive to variations of boilerpressure.

2. A furnace comprising a grate, a bridgewall provided with a passageterminating in a series of contractedopemngs at its upper portion and asecond passage extending through the bridge-wall, both of said passagesopening beneath the grate, means for forcing air to the space beneaththe grate, a deflector situated between the passage openings and.inclined downwardly from the grate, and automatic means for governingthe air forcing means responsive to variations of boiler pressure.

3, A furnace comprising a grate, a bridgegagscs, renders e hrenecessary,

said passages, sai

recess and a second through thebridgewall, both of said passages openingbeneath the grate, means for forcingair to the space beneath His. grate,a deflector situated between the passage-openings, and automatic meansforgovernlng the air-forcing means responsive to variations of boilerpressure;

4. A furnace comprising a grate, a bridgewall provided with a passageterminatirn in a r fess, fire-resisting tile formed wit a series ofcontracted openings and set in said recess, "and a second passageextending through the bridge-wall, both of said passages opening beneaththe grate, means for forcing air to he s ace beneath the grate, atdeflector situated lietween the assage openings and inclined downwar yfrom the grate, and'automatic means for governing the air-forcing meansresponsive to vsriar tions of boiler pressure.

5. A furnace comprising a grate, a bridgei Wall provided with a assageternunating in a series of contracts openings in its upper portion and.a second passage extending through the bridgeavall, both of said passages o ening beneath the grate, a deflector situate between the passageopenings, and. means for supplyin air under pressure to blower, a motorfor operating the lower, a rheostat for controlling the motor, a ressureregulator connected with 'the boi er, and means for communicatingmovement from the regulator to the rheostat.

6. A furnace comprising a grate, a bridgewall provided with a passageterminating in means com rising a inc a recess, fire-resisting tileformed with." a,

series of contracted openings and sct'in said passage extending throughthe bridge-wall, both of saidpassages o ening beneath the grate,a'deflcctor situate between the passage openings and inclined downwardlyfrom the grate, and. means for supplyin air under pressure to,

said passages, sai means com rising a blower, a motor for operatingthelh rheostat for controlling the motor, a pressure regulator connectedwith the boiler, and means for communicating movement of the regulatorto the rheostat.

. The combination with a boiler furnace lower, a

having a grate, of means for forcing air into the'furnace independentlyof fuel su plied thereto, an electric motor for driving tlib airforcingmeans, a rheos'tat connected with the motor, a pressure regulatorassociated with the-boiler and mechanical connections be-- tween thepressure regulator and rheostat whereby the air supply is governed inaccordance with. the amount of steam required,

and definite rates of combustion produced with an indeterminate fuelsupply, said air forcing means having provisions for introducing air tothe furnace both below and above the grate.

8. The combination of a boiler, a combusj tion chamber,means-independent of fuelsupplying means for forcingair into said(JOIHbUStlOII chamber, including an electric motor controlled byconditions within the 1* *ellected without regard to damper regulationof the escape of the products of combustion.

S). The combination with a boiler furnace having a grate, of means forforcing air in to the furnace independent of fuel supplied thereto, anelectric motor'for drivirng the air forcing n'ieans, a rheostatconnected with. the motor, a regulator associated with the boiler, andconnections between the'regulator and rheostat, whereby the air supplyis governed in accordance with the amount of steam required, anddefinite rates of combustion produced with an indeterminate fuel supply,the furnace having a free outlet for the products of combustion, thecapacity of which is not affected bythe operation of the motor, where-(by the motor is utilized so that substantially all the air forcombustion-is introduced and controlled by the motor for supplying airto the furnace. I

10. The combination with aboiler furnace having a grate, of-m'eans forforcing air into the furnace independent of fuel supplied thereto, anelectric motor for driving the airforcing means, a rheostat connectedwith the a motor, a pressure regulator associated with the boiler, andmechanical connections between the pressure regulator and rheostat,whereby the air supply is governed in accordance with the amount ofsteam required,

, and 'delinite rates of combustion produced with an indeterminate fuelsupply, the furnace-having a free outlet for the roducts of combustion,the capacity of whic is not affected by the operation of the motor,whereby the motor is utilized so that substantially all the air forcombustion is introduced and controlled'by the motor for supplying airto the furnace.

In testimony whereof I. have atlixed my signature, in presence of twowitnesses.

. CLARENCE W SMITH. \Yitnesses: J

FRED. W. SMITH: SIDNEY SMITH.

